Origin: This species has been recorded from the Mekong basin in Thailand, Laos and Cambodia. It is also found in Lake Tonle Sap in Cambodia.

Water: Probably not fussy. Neutral tropical conditions should be fine.

Size: Up to 28cm/11. Like the related G. aymonieri, it probably reaches around half this size on average. Large adults are a popular food fish in Cambodia.

Diet: Stomach analyses show that this species is a generalist grazer that feeds predominantly on algae, but also plants, phytoplankton and insects.

Aquarium: Gyrinocheilus aymonieri is a robust and easy-to-keep grazer which does a good job of keeping algae to a minimum. However, the species can become quarrelsome and territorial and may rasp the mucus from the flanks of larger fishes, so you need to be careful what you mix it with. G. pennocki is probably the same. According to Rainboth s Fishes of the Cambodian Mekong, G. pennocki is found on large flat rocks in fast-flowing water. In the dry season it occurs in riffles and rapids in rocky streams.

Breeding: As far as I am aware, this species has not yet been bred in captivity.

Notes: This fish is a member of the cypriniform family Gyrinocheilidae. The genus has three species: G. pennocki, G. pustulosus and the widely available G. aymonieri. The easiest way to tell the three apart is to count the number of branched dorsal fin rays. G. aymonieri has nine, G. pustulosus has 10 and G. pennocki has 11. Gyrinocheilus are adapted for life in fast-flowing water and have greatly reduced swimbladders. A spiracle-like hole exists behind the gill to allow them to breathe while clinging to rocks with the suctorial disc in their mouth.

Availability: These fish were imported by Wildwoods in Middlesex (0208 366 0243) in February. This is the first time I have seen this species for sale in the UK. It s a novelty because it s rarely been exported for the trade, but it s unlikely to prove massively popular.

Price: 2.95.

This article was first published in the April 2007 issue of Practical Fishkeeping. Pictures by Neil Hepworth.